[mhughett]

I've had problems with air bubbles in this engine on my other cars. When I bleed the system it always helps to:

1. Make sure the front end is raised well above the rear so that the air bubbles can come out through the bleed screw. This is important when filling and bleeding the system.
2. Squeeze the lower hose while the engine is running and the heater is on max hot to help force any air though the system

If all else fails, I would drain the system (including the engine block) and start the bleed process over again. It is very important to add coolant very slowly into the expansion tank to minimize the potential pockets of air that get into the system.

Good luck and let us know if this takes care of it. It sure sounds like an air pocket to me as well.